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Yet another Usb to Midi thingy


Jegge
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Hi everybody,

I've planned to build a sammichSID (thanks for the opportunity, Wilba :)), since I just couldn't get on with the modular Sid experience - I found it to tearsome and got lost in the chaos of wires. But a drawback I saw in the sammichSID is the missing midi through, which I've had in the modular version - frankly, I was in need of another midi interface.

Since I've got an arduino recently, I've started experimenting with it and designed a Usb to Midi interface around the Atmel platform. The project started out on the breadboard, moved up to a prototype board and currently I am waiting for the real pcb prototypes to arrive.

The design goals were: cheap, small, no smd, no drivers!

Features:

  • 1 Usb, 1 midi in, 1 midi out
  • No SMD
  • No drivers required (so far tested on Windows XP and Linux 2.6)
  • Small: PCB is 68 x 46 mm (fits in the GEH KS 35 from Reichelt)
  • 3 Leds: 1 Power / Error, 1 Midi in, 1 Midi out
  • Powered by Atmega48
  • Cheap: parts and case about 6 EUR, PCB would be around 3 EUR (when ordered in quantities 150 and up)
  • Open Source

    Cons:

    • There are three variants already, who'd need one more?
    • In system programming capability omitted due to size restrictions, a separate programmer would be needed if you want to modify the firmware
    • Only 1 midi in, 1 midi out :)
    • Does not fit in the mbhp, since it uses an atmel controller and completely different firmware

    If there is enough interest, I will try to make this available as a kit. The estimated price would be around 10 EUR (excluding packaging and shipping), and I'm cutting my own throat :)

    CU Jegge

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i was also fearsome, but with some education (i.e. youtube tutorials) beforehand, i was able to solder the GM5 as my first SMD part ever. not very many problems, except my desoldering braid sucks (in a bad sense).

now i'm waiting for the parts to arrive so i can assemble the thing and see if it works. :-)

lose the fear :-)

Edited by bilderbuchi
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Powered by Atmega48

Atmega chips have not hardware usb support - it mean it provide usb support in the firmware level, i know popular realisation is V-USB, but it's unfortunately doesn't support speeds higher than 6400 bps = but midi speed is 31250 bps. So this is not full speed usb2midi converter. any atmega don't provide really good usb2midi device.

I think about chips like CP2102 and FT232 they are about $5 an they are able to support uart2usb full speed, but i have not yet tested them in my hands :)

GM5 is bad variant because of: Is there anybody tell me where i can buy it cheap and fast in my places???

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GM5 is bad variant because of: Is there anybody tell me where i can buy it cheap and fast in my places???

GM5 is the best, really - not only is it fast, cheap and easy to get from TK, but the Windows driver is multi-client!

I tried a lot of commercial MIDI-interfaces through time, and none of them rocks like GM5 - also, i can't be bothered with drivers missing, unsupported OS'es and stuff.. a quick forum search will reveal that practically no bad arguments has been made about the GM5 ;)

Besides that, i just think it's pure magic that enables such a tiny chip to control 5 MIDI ports simultaneously :P

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Indeed, I use the V-USB driver. But up to now I haven't encountered speed problems - I will update my test app so that I can measure the time it takes me to transfer large blocks, you made me curious :) As far as I understood reading their forums, the transfer speed they got with their tests was around 7000 bytes/second. The speed of my device is probably less. But midi only needs around 3900 bytes/second, so I suppose that is still covered.

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As far as I understood reading their forums, the transfer speed they got with their tests was around 7000 bytes/second.

I think nor bytes but bits. And this is 8 times slower.

Pft. This is just wrong :)

The gm5 is an awesome midi interface. TK sells them for 4,50eur iirc, that is cheap.

As i can understand. That chip is ordered in 100-1000 pcs by TK from the factory and he wait for 100-1000 peoples who want to buy one gm5. Ok maybe i'm wrong and i may buy TODAY, but how much money to send that 5euro's gm5 to Russia ?

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This is going hella of topic... Sending the chip to russia would be ~1,50eur.

Good, but i'm still think it's strange to use any exclusive chips in DIY.

OK, for Jegge and other topic readers i like to share this link: http://swit4.ru/files/UART2MIDI.rar (i think that device have potential to do much than one midi-out+midi-in+usb but up to 3midi-ins/outs at least). It's based on the atmega8 and ft232rl for usb connecting. Now this is usb2midi converter only it's not an alternative for gm5 or another midibox usb modules. It also require for com2midi windows driver (included), it's not good idea for future compatibility.

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